Generally, a mass spectrometer is used to analyze a gaseous sample. To inject the gaseous sample into the mass spectrometer, a gaseous sample injection valve which may inject the gaseous sample into a chamber of the mass spectrometer which is in a vacuum state is needed.
To analyze the gaseous sample, it is necessary to inject the gaseous sample corresponding to 1×10−4 to 1×10−5 torr with respect to a volume of the chamber which is in the vacuum state. In a method of injecting the gaseous sample into the vacuum chamber, there are a method which increases flow resistance using a conventional capillary tube or an orifice and reduces a gas injection amount, and a method in which an auxiliary pump is provided at a gas inlet port so that most of the gaseous sample is divided and discharged and only part of the gaseous sample is injected.
Meanwhile, it is necessary to reduce a size and a weight of the mass spectrometer to allow the mass spectrometer to be movable in order to analyze a surrounding atmosphere or because of difficulty in moving the gaseous sample, etc. Since this movable mass spectrometer is driven by a battery, it is necessary to inject the gaseous sample using a solenoid valve operated by a pulse signal in order to reduce a load of a vacuum pump having great power consumption.
However, in a conventional gaseous sample injection, the method using the capillary tube or the orifice has a limitation in a process of reducing a size of a device. Further, when the gaseous sample is injected through the dividing and discharging process, the pump is added to a sample injection device, and thus it is difficult to reduce a size of the device
Further, in the conventional art, when a minute amount of the gaseous sample is injected using the solenoid valve, an amount of the injected gaseous sample is not constant, and thus an ion concentration of a mass spectrum, which is measured from the vacuum chamber, is not constant either, and a gaseous component analysis is affected.